● Mitochondrial disease pedigree
○ Several diseases of human nervous system are caused by mutations in
mitochondrial genome
■ Mutations passed from mothers to children
■ Symptoms vary due to heteroplasmy (existence of two or more mtDNA
variants) inherited
- Endosymbiotic Theory- Both mitochondria and chloroplasts were acquired by absorbing
ancient prokaryotes that symbiotically worked together and eventually made eukaryotic
cells.
● Structure and function of mitochondria
- Mitochondria is membrane bound cytoplasmic organelles
- Produces ATP through Krebs cycle and oxidative phosphorylation
● Comparing prokaryotic and eukaryotic cells
- Plasma membrane
- Semifluid substance called cytosol/cytoplasm
- Contain chromosomes that carry genes
- Have ribosomes that make proteins
● Mitochondria have characteristics of prokaryotic cells
- Small, circular genome
- DNA sequences similar to bacteria
- No eukaryotic introns, no histones
- Internal transcription, translation
- Prokaryotic ribosomes
- Divide separately from cell (nuclear fission)
- Use N-formyl methionine and tRNAfmet in translation
● Uniparental, maternal inheritance of cytoplasm
● Cytoplasmic segregation of mitochondria
- Mitochondrial diseases (MERRF)- myoclonic epilepsy and ragged red fiber
disease
○ Mutations in mitochondrial tRNA, Dangerous effects on ATP production, Tissue
distribution of mutant mitochondria and MERRF phenotype
Heteroplasmic- mixed, wild type and mutant
mitochondria. Creates heteroplasmic and
homoplasmic cells that are passed to daughter
cells. Some cells end up with all mutant, or all
wild type, or mixture.
Pedigree of Mitochondrial Disease- passed
from mother to all children, never from father
Mitochondrial Replacement Therapy (MRT)
○ Several diseases of human nervous system are caused by mutations in
mitochondrial genome
■ Mutations passed from mothers to children
■ Symptoms vary due to heteroplasmy (existence of two or more mtDNA
variants) inherited
- Endosymbiotic Theory- Both mitochondria and chloroplasts were acquired by absorbing
ancient prokaryotes that symbiotically worked together and eventually made eukaryotic
cells.
● Structure and function of mitochondria
- Mitochondria is membrane bound cytoplasmic organelles
- Produces ATP through Krebs cycle and oxidative phosphorylation
● Comparing prokaryotic and eukaryotic cells
- Plasma membrane
- Semifluid substance called cytosol/cytoplasm
- Contain chromosomes that carry genes
- Have ribosomes that make proteins
● Mitochondria have characteristics of prokaryotic cells
- Small, circular genome
- DNA sequences similar to bacteria
- No eukaryotic introns, no histones
- Internal transcription, translation
- Prokaryotic ribosomes
- Divide separately from cell (nuclear fission)
- Use N-formyl methionine and tRNAfmet in translation
● Uniparental, maternal inheritance of cytoplasm
● Cytoplasmic segregation of mitochondria
- Mitochondrial diseases (MERRF)- myoclonic epilepsy and ragged red fiber
disease
○ Mutations in mitochondrial tRNA, Dangerous effects on ATP production, Tissue
distribution of mutant mitochondria and MERRF phenotype
Heteroplasmic- mixed, wild type and mutant
mitochondria. Creates heteroplasmic and
homoplasmic cells that are passed to daughter
cells. Some cells end up with all mutant, or all
wild type, or mixture.
Pedigree of Mitochondrial Disease- passed
from mother to all children, never from father
Mitochondrial Replacement Therapy (MRT)
